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Egorov O.V. 1 , Lozinskaya T.A. 1 , Moiseev A.V. 2

The structure and kinematic of gas in the center of recent star-formation burst in the Irr Galaxy IC10. Egorov O.V. 1 , Lozinskaya T.A. 1 , Moiseev A.V. 2 1 Sternberg Astronomical Institute, Moscow, Russia

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Egorov O.V. 1 , Lozinskaya T.A. 1 , Moiseev A.V. 2

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  1. The structure and kinematic of gas in the center of recent star-formation burst in the Irr Galaxy IC10. Egorov O.V.1, Lozinskaya T.A.1, Moiseev A.V.2 1Sternberg Astronomical Institute, Moscow, Russia 2Special Astrophysical Observatory of Russian Academy of Science, NizhniiArkhyz, Karachai-Cherkessia, Russia Nearby Dwarf Galaxies, 14-18 sep 2009

  2. About IC10 • The dwarf irregular galaxy IC10 is a nearest sturburst galaxy • It have the highest number of WR stars per luminosity unit in the LG • The recent burst of star formation is localized mainly in its south-eastern part, where the densest cloud of HI, molecular CO cloud and complex of brightest emission nebulae locate. This region is brightest in Hα and [SII]λ6717 lines.

  3. Marks on the images WR stars marks by stars symbols and named according to the catalogs from Massey et all (2002) and Royer et all (2001) Clustersfrom Hunter (2001) marks by circle symbols according with their size. We consider a region with burst of star formation which contain two HII-regions, named according to catalog Hodge, Lee (1990) as HL111 and HL106.

  4. Sources of gas ionization The main sources of ionization of HL111 nebulaare M24 object, which represents close group of six blue stars, four of which are possible WR candidates, and three stellar clusters 4-1, 4-2 and 4-7. The bright shell-like HL106 nebula most probably ionized by WR stars R2 and R10 and by clusters 4-3 and 4-4.

  5. Observations • The observations were performed at the 6-m telescope (SAO RAS) with: • SCORPIO focal reducer operating in the scanning Fabry-Perot interferometer mode in Hα and [SII]λ6717 lines • MPFS field spectrograph • All data reduction was provide in IDL. • We reanalyzed the 21-cm line data cube from VLA, kindly provided by Wilcots and Miller, to get more detailed local HI kinematics in the area of HL111 and HL106. • Mosaic of CO clouds made using the data from Leroy et all (2006) • All velocities are heliocentric

  6. Kinematics of ionized gas Investigation of ionized gas made in three steps. • We made a system of horizontal and vertical “position-velocity” diagrams (pv-diagrams) through all starburst region. • Using this pv-diagrams we selected most interest places and plot Hα and [SII]λ6717 line profiles there. • We plot Hα, [SII]λ6717 and [NII]λ6583 line profiles from MPFS data, that was averaged over most part of field, and compared them with IPF line profiles from same areas.

  7. Kinematics of ionized gas Investigation of ionized gas made in two steps. • We made a system of horizontal and vertical “position-velocity” diagrams (pv-diagrams) through all starburst region. • Using this pv-diagrams we selected most interest places and plot Hα and [SII]λ6717 line profiles there. • We plot Hα, [SII]λ6717 and [NII]λ6583 line profiles from MPFS data, that was averaged over most part of field, and compared them with IPF line profiles from same areas.

  8. Kinematics of ionized gas Investigation of ionized gas made in two steps. • We made a system of horizontal and vertical “position-velocity” diagrams (pv-diagrams) through all starburst region. • Using this pv-diagrams we selected most interest places and plot Hα and [SII]λ6717 line profiles there. • We plot Hα, [SII]λ6717 and [NII]λ6583 line profiles from MPFS data, that was averaged over most part of field, and compared them with IPF line profiles from same areas.

  9. Kinematics of ionized gas

  10. Kinematics of ionized gas

  11. Kinematics of ionized gas Hαpv-diagrams [SII]λ6717 pv-diagrams

  12. Kinematics of ionized gas

  13. Kinematics of ionized gas

  14. Kinematics of ionized gas Summary of the main results • The velocity of ionized gas in the starburst region is from V(hel) =-325 km/s to V(hel) =-350 km/s. • The mean value in Hα line is V(hel) = - 335 km/s. • The expansion velocity of the bright HL111 and HL106 shells is no more than 10-15 km/s. • In some regions inside the HL111 shell we find profile asymmetry in the red wing at the 2-6% of maximal intensity at the velocities from -250 km/s to -230 km/s • The weak details in the red wing of Hαline at 2-5% level in HL106 are in the range V(hel)=-280 km/s to V(hel)=-230 km/s. • The weak details in the red and blue wings are seen in the western part of the region between the HL106 and HL111 nebulae (their velocities above V(hel)= -260 km/s and V(hel)= -420 km/s)

  15. Kinematics of HI • There is the neutral shell directly outside the ionized nebula HL111. The mean velocity of this HI shell -333 -- -336 km/s. The expansion velocity of the neutral shell is about 10-15 km/s. • The similar neutral shell is distinguished around the nebula HL106; its expansion velocity is about 10-15 km/s.

  16. Kinematics of HI • There is the neutral shell directly outside the ionized nebula HL111. The mean velocity of this HI shell -333 -- -336 km/s. The expansion velocity of the neutral shell is about 10-15 km/s. • The similar neutral shell is distinguished around the nebula HL106; its expansion velocity is about 10-15 km/s.

  17. Kinematic of HI In the region between HL106 and HL111 both smooth mean HI velocity changes from north-east towards south-west and the local perturbations of the neutral gas can be seen. The velocities of the “perturbed” neutral gas change in range from +30 km/s to -30 km/s relative to mean velocity.

  18. Structure of the investigated region HL111 HL106 Most probably M24 stars are located on the backside of densest HI cloud. We see a bright low-velocity details from coming side of blister-like shell and faint high velocity details from leaving side • Only in region where CO cloud locate the color excess reach a local maximum (E(B-V)=1.3) • Border of CO cloud concur with Hα shell. • We suppose that CO cloud locate in front of HL106 nebula and there is interaction between them • Probably the thin HL106 shell was formed as a result of photodissociation of the molecular gas on the border of CO cloud and ionization from the WR R10 and R2 and clusters 4-3 and 4-4

  19. Summary • We investigated the kinematics of the region of recent burst of star formation that contain a two brightest HII-region – HL111 and HL106. Based on results of this work we made assumptions about structure of this region • We found at first time a high-velocity details (about 100 km/s from the mean velocity) in cavern of HL111 and in HL106 nebula • We estimated a velocity of expansion of HL111 and HL106 (about 10-15 km/s). • We found neutral HI shells around HL111 and HL106 end estimate their expansion velocities (about 10-15 km/s). • The work is continuing and all results will be published soon Thanks for attention The work is supported by the Russian Foundation for Basic Research (project 07-02-00227) and is based on observation material obtained with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences founded by the Ministry of Science of the Russian Federation (registration number 01-43).

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